A set of D2D resources (hereinafter referred to as a ‘D2D resource set’) may be used for repeated transmission of a Medium Access Control Protocol Data Unit (MAC PDU) that delivers a discovery signal (hereinafter referred to as a discovery MAC PDU) within a discovery period.

FIG. 6 is a diagram illustrating an example of a D2D discovery resource set according to an exemplary embodiment.

Referring to FIG. 6, a D2D discovery resource set within a discovery period may include contiguous D2D discovery resources or non-contiguous D2D discovery resources, in the time domain. That is, repeated D2D discovery resources in the D2D discovery resource set may be contiguous or non-contiguous in the time domain.

FIG. 7 is a diagram illustrating examples of a D2D discovery resource configuration structure in a D2D discovery resource set according to an exemplary embodiment.

Referring to FIG. 7, patterns indicate resources included in each D2D discovery resource set. A plurality of D2D discovery resource sets may exist in a single discovery period, and D2D discovery resources in a single D2D discovery resource set may be contiguous (a) or non-contiguous (b) in the time domain, and may be arranged in the frequency domain based on frequency hopping (inter-subframe frequency hopping). From the perspective of an Rx UE, a discovery signal may be monitored within a resource pool for D2D reception. The resource pool for D2D reception may be in a form of a super set, when compared to a resource pool for D2D transmission.